problem detected caused by cycle power KRONOS

[Swatboy21]

Hello guys i hope someone could help me with this problem on Kronos. I haven't seen this problem to me earlier it happened suddenly now after the message "problem has been detected which may have been caused by cycling power too quickly" it say they turn off the kronos and wait 10 sec to turn on. I get the message after a while from the moment i turn on the kronos. I hope someone can help me with this problem thanks.

[Falcon2e]

This has been discussed many times here, but usually it is caused by an electrical problem. Low voltage is possible. Are you using a UPS unit?

Do you have the most current firmware available installed?

I had the same problem a few years ago. After updating my OS AND firmware plus using a UPS, life is good.

[GregC]

yeah, maybe a 10 second wait before power on is too soon.

wait 30-40 seconds

[ronnfigg]

Make sure you IEC cable is solidly inserted at both ends.

[Liviou2004]

We'll never insist enough : the Kronos is based on computer elements. So it needs a perfectly stabilized voltage, far more than all others synths. The Kronos is highly micro-cut sensitive.

An UPS unit is essential to avoid bad surprises.

[Ron]

So not to complicate the original subject but to promote some discussion on the need for a UPS....

I am not sure but I think the Kronos uses a "switching" power supply? In general, switching power supplies are NOT very sensitive to input voltage variations. In fact, it is one of their main advantages. They are also less sensitive to the blips and dips that are almost always present on any power system.

That said, I agree with using a UPS. However, not all UPS are created equally. Almost any UPS will provide some immunity, but with certain types, you are still connected to the mains supply until the UPS is triggered to back up mode. Once triggered, the UPS disconnects from the mains to supply power from its battery (converted to AC) until the mains power is restored. During this process, the Kronos will see any problem on the maiins, e.g. dropping voltage until the UPS is triggered into action. The Kronos will also see the switch transients associated with the change over from mains to UPS and back.

While I have some knowledge on this subject, I am by no means an expert. Maybe someone more knowledgeable could chime in?

PS - I looked a bit for the input voltage specs on the Kronos but could not find them.

[ronnfigg]

We'll never insist enough : the Kronos is based on computer elements. So it needs a perfectly stabilized voltage, far more than all others synths. The Kronos is highly micro-cut sensitive.

An UPS unit is essential to avoid bad surprises.

Can you cite a source for your declaration please? Thanks.

[voip]

The Kronos uses a wide input votage range (90-264V AC) switched mode power supply (SMPS) and, as Ron said, these supplies are relatively unaffected by input voltage variations. However, SMPSs tend not to be particularly good at rejecting transients (high voltage spikes) in the mains supply, nor radio frequency interference on the supply lines. Not all switched mode power supply manufacturers give an indication of the supply voltage rejection, but those that do, typically quote a figure of 60dB. This means that, as an example, for a 1kV impulse type transient on the mains supply, which is not uncommon in mains supplies, even in the absence of thunderstorms, around 1V will be superimposed on the PSU output(s), so the potential is there to produce instability, or even damage to circuitry. It is up to the designer to mitigate against this, and the Korg Kronos designers have included a mains input filter to the Kronos, which, from the spec sheet, gives around 10dB of attenuation to a typical "normal mode" mains spike waveform, so 1kV in on the supply will give around 0.3V out. But imagine, during a thunderstorm, surges can be much larger e.g. 10kV, which, based on the above assumptions of 60dB supply rejection by the SMPS plus 10dB by the mains filter, may result in 3V imposed on the supply outputs on the Kronos. This is where a UPS (uninterruptible power supply) comes into play, because all UPSs will attenuate surges and RF interference on the mains supply to some extent. By how much depends on the design, but there will always be some. The best UPSs are likely to be the ones that constantly generate their mains outputs from the UPS battery rails and will tend to be rather more expensive. In fairness, the Kronos design engineers, in recognisiton of this, have put quite substantial filtering on the 12V supply lines coming from the SMPS, but a rather less substantial design for the 5V supply though.

The second benefit from having a UPS is that it will continue to provide power to the Kronos when the mains supply is interrupted. The worst case scenario would be loss of power during an extensive write cycle to the Kronos SSD e.g. when saving PCGs or sampling data, or during installation of a Kronos EXs type expansion.

By the way, one prolific source of radio frequency interference on the mains wiring is powerline ethernet i.e. ethernet over the mains supply cabling. These are seriously bad karma!! The PLT adaptors impose, on average, several volts at radio frequency on the mains wiring. The nature of the modulation used, OFDM (orthogonal frequency division multiplexing) means that the voltage excursions imposed on the mains will have peak values much much higher than the average. If you have PLT adaptors (you probably do but don't realise) get rid of them!! Or at least disable the PLT functionality using the device's engineering menus.

One of the forum members, Antony Sharmman, mentions in his signature that he has designed automotive SMPS, which operate in quite a harsh environment, so will have some experience to bring to this discussion.

.

[Sweat]

The UPS units I have used over the years have been helpful. However, it seems like the batteries go bad after about 3 years.

Full power interruptions are not a bad problem in my area. Instead, I have been in some venues with fluctuating or noisy power. So, now I use an AVR (Automatic Voltage Regulator).

Here is a good article explaining differences.
https://www.sweetwater.com/insync/power ... explained/

[AntonySharmman]

Maybe someone more knowledgeable could chime in?

I have many times spoken about SMPS & Kronos UPS for the last 8 years , as an expert designer of switching topology for advanced medical gear.
I've also analyzed the specific Kronos ENHANCE PSU , so I will write you all once again the following FYI :

- Kronos PSU SMPS , has double "Π" AC input LC filtering that will completely struggle/suppress any AC over-voltage spikes (even 1KV) , next a full
bridge rectifier follows that regulates 85-400 Volt AC input voltage into DC voltage with over 330μF/450V huge capacity filter that will completely
eliminate any AC / HF carrier and independently from input instant voltage values or continues voltage fluctuations , output will be extremely stable
if lowest voltage margin is 85 volts.
- Also large regulation capacitor will provide power supply to Kronos circuity for over 0,4 seconds if net power is interrupted (E=1/2*C*V²).
A convenient way to test that is to quickly turn OFF & ON Kronos power switch and see that Kronos won't be affected , so any UPS will turn in inverter
mode 4 times faster than needed.

- The case of continues net over-voltage (>450V) where all your connected home devices will be burned , only primary switching stage of Capacitors ,
diodes & mosfets will be burned , but output will never be increased from nominal values !
The extreme scenario of thunderstorm spike strike will completely destroy UPS and any equipment in place even if are turned OFF , including yourselves
in 2m distance from net sockets ... so please be reasonable when talking about KVs !

- UPS is not needed for regular home/studio use if you have a stable electricity network except only in critical cases of software/firmware updating
and when saving very important files of your setup in storage media.
A small and cheap UPS module (200W max) of 50$ must be always included in your gigging gear since you never know net power conditions you will meet there !

- If Kronos PSU will fail then your Kronos will be completely dead without any warning at all.

- Servicing client's Kronos keyboards for many years ( WavesArt's local service) , have provided me statistics that all screen messages/warnings of
boot failure are not related to PSU and 95% are caused by SSD media failure and communication with motherboard , exactly as in your PC/Laptop ...

Hope this helps

[voip]

A word of caution regarding filtering components in SMPS. Filtering will never completely suppress incoming energy, but only by a number of dB. Secondly, there is no such thing as an RF ground, and pulse energy can be considered to be in the RF domain. Pulses, and RF in general, WILL find their way through, or around, the SMPS, with varying degrees of attenuation. I have seen 500V test pulses into the mains input of an SMPS produce processor glitches, and corruption of NAND flash in telecoms grade equipments in early stage development, and the Kronos SMPS is nowhere near telecoms grade, nor the Kronos itself. The huge capacity of the main reservoir capacitor is not necessarily much of a barrier to RF, because of the ESR of these components.

[AntonySharmman]

I wrote details about filtering , only after first stage of induction filter , frequencies over 20KHz are completely vanished , also a direct line
filtering with an electrolytic capacitor of low ESR of over 100μF will eliminate RF over 1 MHz (>-90db) and RF always is passing from circuit
grounding if measured , but never at actual dipole output of filter , those remarks need laboratory benchmarks and much experience due to
understand exactly of what I mean.

I'm also very familiar to RF effects as a radio amateur that using handmade KWs of broadcasting power amplifiers in whole RF spectrum ,
so I ensure you that absolutely nothing will pass through SMPS , but EMF RF skin phenomenon will definitely affect any single wire in your
devices and will create ESR demodulation in every single component or logic gate , especially if closer AM modulation RF power is emitted !
When I broadcast at 80m /AM-SSB in my ham shack , my sister's Hi-Fi system loudspeakers are demodulating my dialog loudly although
her system amplifier is completely turned off ...

Net grounding and keyboard chassis itself will create an antenna receiver equivalent , it's commonly known in electric engineering , but rather
an extreme case to discuss and inform Kronos end-users !

[Swatboy21]

Thank you for all your answers, i tried my best for my Kronos i changed my ram update my firmware but the problem still occur. So i see that the only thing i can do is buy an Ups unit can someone tell me how much it will cost and what should i look for when i buy jt

[GregC]

U should find highly rated UPS on Amazon

However, that only treats a symptom.

A UPS doesn't solve your Kronos problem

Korg service time

[ronnfigg]

So not to complicate the original subject but to promote some discussion on the need for a UPS....

I am not sure but I think the Kronos uses a "switching" power supply? In general, switching power supplies are NOT very sensitive to input voltage variations. In fact, it is one of their main advantages. They are also less sensitive to the blips and dips that are almost always present on any power system.

That said, I agree with using a UPS. However, not all UPS are created equally. Almost any UPS will provide some immunity, but with certain types, you are still connected to the mains supply until the UPS is triggered to back up mode. Once triggered, the UPS disconnects from the mains to supply power from its battery (converted to AC) until the mains power is restored. During this process, the Kronos will see any problem on the maiins, e.g. dropping voltage until the UPS is triggered into action. The Kronos will also see the switch transients associated with the change over from mains to UPS and back.

While I have some knowledge on this subject, I am by no means an expert. Maybe someone more knowledgeable could chime in?

PS - I looked a bit for the input voltage specs on the Kronos but could not find them.

Well it's not much of an Uninterruptible Power Supply if it does what you say.